1. Field of the Invention
The present invention relates to vehicle passenger safety modules that use pressurized gas from an inflator to deploy an airbag between passengers and the interior of a vehicle in the event of a collision. In particular, the present invention pertains to the structure associated with the inflator that effects the abrupt release of the pressurized inflation gas contained therein.
2. Background
An airbag for a vehicle passenger safety module includes an inflation portion that captures pressurized gas from an inflator, thereby becoming a gas-filled cushion interposed between a vehicle occupant and the interior vehicle surfaces surrounding that occupant.
The inflator is ignited electrically in response to a signal from a momentum monitor carried in the vehicle. The inflator is a closed structure having walls sufficiently sturdy to safely retain inflation gas at high pressures. The pressurized inflation gas is released from the inflator at a high velocity by abruptly opening the discharge end of the inflator. The inflation gas initially passes through a gas diffuser that redirects the inflation gas in directions and in quantities that are optimally suited to nondestructively but efficiently inflate an airbag cushion.
The structure actually effecting the abrupt opening of the inflator is the rupture features of the inflator. The rupture feature is activated in response to a pressure impulse of predetermined amount generated in the inflator.
A typical rupture feature employs a thin rupture disc that is supported about the periphery thereof across the intended outflow path of pressurized inflation gas. The rupture disc is secured to the interior of a sturdy frame component that is used to close the discharge end of the inflator. A pressure impulse of predetermined amount generated in the inflator causes destructive forces in the rupture disc that burst the rupture disc permitting the pressurized inflation gas in the inflator to escape at high velocity.